Enhancement on Deterministic stage (#1972)

* fuzzer: init commit based on aflpp 60dc37a8cf09f8e9048e4b6a2204d6c90b27655a

* fuzzers: adding the skip variables and initialize

* log: profile the det/havoc finding

* log: add profile log output

* fuzzers: sperate log/skipdet module

* fuzzers: add quick eff_map calc

* fuzzers: add skip_eff_map in fuzz_one

* fuzzers: mark whole input space in eff_map

* fuzzers: add undet bit threshold to skip some seeds

* fuzzers: fix one byte overflow

* fuzzers: fix overflow

* fix code format

* add havoc only again

* code format

* remove log to INTROSPECTION, rename skipdet module

* rename skipdet module

* remove log to stats

* clean redundant code

* code format

* remove redundant code format check

* remove redundant doc

* remove redundant objects

* clean files

* change -d to default skipdet

* disable deterministic when using CUSTOM_MUTATOR

* revert fix

1 files changed, 403 insertions, 0 deletions

diff --git a/src/afl-fuzz-skipdet.c b/src/afl-fuzz-skipdet.c
new file mode 100644
index 00000000..e52d59a3
--- /dev/null
+++ b/src/afl-fuzz-skipdet.c
@@ -0,0 +1,403 @@
+
+
+#include "afl-fuzz.h"
+
+void flip_range(u8 *input, u32 pos, u32 size) {
+
+  for (u32 i = 0; i < size; i++)
+    input[pos + i] ^= 0xFF;
+
+  return;
+
+}
+
+#define MAX_EFF_TIMEOUT (10 * 60 * 1000)
+#define MAX_DET_TIMEOUT (15 * 60 * 1000)
+u8 is_det_timeout(u64 cur_ms, u8 is_flip) {
+
+  if (is_flip) {
+
+    if (unlikely(get_cur_time() - cur_ms > MAX_EFF_TIMEOUT)) return 1;
+
+  } else {
+
+    if (unlikely(get_cur_time() - cur_ms > MAX_DET_TIMEOUT)) return 1;
+
+  }
+
+  return 0;
+
+}
+
+/* decide if the seed should be deterministically fuzzed */
+
+u8 should_det_fuzz(afl_state_t *afl, struct queue_entry *q) {
+
+  if (!afl->skipdet_g->virgin_det_bits) {
+
+    afl->skipdet_g->virgin_det_bits =
+        (u8 *)ck_alloc(sizeof(u8) * afl->fsrv.map_size);
+
+  }
+
+  if (!q->favored || q->passed_det) return 0;
+  if (!q->trace_mini) return 0;
+
+  if (!afl->skipdet_g->last_cov_undet)
+    afl->skipdet_g->last_cov_undet = get_cur_time();
+
+  if (get_cur_time() - afl->skipdet_g->last_cov_undet >= THRESHOLD_DEC_TIME) {
+
+    if (afl->skipdet_g->undet_bits_threshold >= 2) {
+
+      afl->skipdet_g->undet_bits_threshold *= 0.75;
+      afl->skipdet_g->last_cov_undet = get_cur_time();
+
+    }
+
+  }
+
+  u32 new_det_bits = 0;
+
+  for (u32 i = 0; i < afl->fsrv.map_size; i++) {
+
+    if (unlikely(q->trace_mini[i >> 3] & (1 << (i & 7)))) {
+
+      if (!afl->skipdet_g->virgin_det_bits[i]) { new_det_bits++; }
+
+    }
+
+  }
+
+  if (!afl->skipdet_g->undet_bits_threshold)
+    afl->skipdet_g->undet_bits_threshold = new_det_bits * 0.05;
+
+  if (new_det_bits >= afl->skipdet_g->undet_bits_threshold) {
+
+    afl->skipdet_g->last_cov_undet = get_cur_time();
+    q->skipdet_e->undet_bits = new_det_bits;
+
+    for (u32 i = 0; i < afl->fsrv.map_size; i++) {
+
+      if (unlikely(q->trace_mini[i >> 3] & (1 << (i & 7)))) {
+
+        if (!afl->skipdet_g->virgin_det_bits[i])
+          afl->skipdet_g->virgin_det_bits[i] = 1;
+
+      }
+
+    }
+
+    return 1;
+
+  }
+
+  return 0;
+
+}
+
+/*
+  consists of two stages that
+  return 0 if exec failed.
+*/
+
+u8 skip_deterministic_stage(afl_state_t *afl, u8 *orig_buf, u8 *out_buf,
+                            u32 len, u64 before_det_time) {
+
+  u64 orig_hit_cnt, new_hit_cnt;
+
+  if (afl->queue_cur->skipdet_e->done_eff) return 1;
+
+  if (!should_det_fuzz(afl, afl->queue_cur)) return 1;
+
+  /* Add check to make sure that for seeds without too much undet bits,
+     we ignore them */
+
+  /******************
+   * SKIP INFERENCE *
+   ******************/
+
+  afl->stage_short = "inf";
+  afl->stage_name = "inference";
+  afl->stage_cur = 0;
+  orig_hit_cnt = afl->queued_items + afl->saved_crashes;
+
+  u8 *inf_eff_map = (u8 *)ck_alloc(sizeof(u8) * len);
+  memset(inf_eff_map, 1, sizeof(u8) * len);
+
+  if (common_fuzz_stuff(afl, orig_buf, len)) { return 0; }
+
+  u64 prev_cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
+  u64 _prev_cksum = prev_cksum;
+
+  if (MINIMAL_BLOCK_SIZE * 8 < len) {
+
+    // u64 size_skiped = 0, quick_skip_exec = total_execs, quick_skip_time =
+    // get_cur_time();
+    u64 pre_inf_exec = afl->fsrv.total_execs, pre_inf_time = get_cur_time();
+
+    /* if determine stage time / input size is too small, just go ahead */
+
+    u32 pos = 0, cur_block_size = MINIMAL_BLOCK_SIZE, max_block_size = len / 8;
+
+    while (pos < len - 1) {
+
+      cur_block_size = MINIMAL_BLOCK_SIZE;
+
+      while (cur_block_size < max_block_size) {
+
+        u32 flip_block_size =
+            (cur_block_size + pos < len) ? cur_block_size : len - 1 - pos;
+
+        afl->stage_cur += 1;
+
+        flip_range(out_buf, pos, flip_block_size);
+
+        if (common_fuzz_stuff(afl, out_buf, len)) return 0;
+
+        flip_range(out_buf, pos, flip_block_size);
+
+        u64 cksum =
+            hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
+
+        // printf("Now trying range %d with %d, %s.\n", pos, cur_block_size,
+        //     (cksum == prev_cksum) ? (u8*)"Yes" : (u8*) "Not");
+
+        /* continue until we fail or exceed length */
+        if (cksum == _prev_cksum) {
+
+          cur_block_size *= 2;
+
+          if (cur_block_size >= len - 1 - pos) break;
+
+        } else {
+
+          break;
+
+        }
+
+      }
+
+      if (cur_block_size == MINIMAL_BLOCK_SIZE) {
+
+        /* we failed early on*/
+
+        pos += cur_block_size;
+
+      } else {
+
+        u32 cur_skip_len = (cur_block_size / 2 + pos < len)
+                               ? (cur_block_size / 2)
+                               : (len - pos - 1);
+
+        memset(inf_eff_map + pos, 0, cur_skip_len);
+
+        afl->skipdet_g->inf_prof->inf_skipped_bytes += cur_skip_len;
+
+        pos += cur_skip_len;
+
+      }
+
+    }
+
+    afl->skipdet_g->inf_prof->inf_execs_cost +=
+        (afl->fsrv.total_execs - pre_inf_exec);
+    afl->skipdet_g->inf_prof->inf_time_cost += (get_cur_time() - pre_inf_time);
+    // PFATAL("Done, now have %d bytes skipped, with exec %lld, time %lld.\n",
+    // afl->inf_skipped_bytes, afl->inf_execs_cost, afl->inf_time_cost);
+
+  } else
+
+    memset(inf_eff_map, 1, len);
+
+  new_hit_cnt = afl->queued_items + afl->saved_crashes;
+
+  afl->stage_finds[STAGE_INF] += new_hit_cnt - orig_hit_cnt;
+  afl->stage_cycles[STAGE_INF] += afl->stage_cur;
+
+  /****************************
+   * Quick Skip Effective Map *
+   ****************************/
+
+  /* Quick Effective Map Calculation */
+
+  afl->stage_short = "quick";
+  afl->stage_name = "quick eff";
+  afl->stage_cur = 0;
+  afl->stage_max = 32 * 1024;
+
+  orig_hit_cnt = afl->queued_items + afl->saved_crashes;
+
+  u32 before_skip_inf = afl->queued_items;
+
+  /* clean all the eff bytes, since previous eff bytes are already fuzzed */
+  u8 *skip_eff_map = afl->queue_cur->skipdet_e->skip_eff_map,
+     *done_inf_map = afl->queue_cur->skipdet_e->done_inf_map;
+
+  if (!skip_eff_map) {
+
+    skip_eff_map = (u8 *)ck_alloc(sizeof(u8) * len);
+    afl->queue_cur->skipdet_e->skip_eff_map = skip_eff_map;
+
+  } else {
+
+    memset(skip_eff_map, 0, sizeof(u8) * len);
+
+  }
+
+  /* restore the starting point */
+  if (!done_inf_map) {
+
+    done_inf_map = (u8 *)ck_alloc(sizeof(u8) * len);
+    afl->queue_cur->skipdet_e->done_inf_map = done_inf_map;
+
+  } else {
+
+    for (afl->stage_cur = 0; afl->stage_cur < len; afl->stage_cur++) {
+
+      if (done_inf_map[afl->stage_cur] == 0) break;
+
+    }
+
+  }
+
+  /* depending on the seed's performance, we could search eff bytes
+     for multiple rounds */
+
+  u8 eff_round_continue = 1, eff_round_done = 0, done_eff = 0, repeat_eff = 0,
+     fuzz_nearby = 0, *non_eff_bytes = 0;
+
+  u64 before_eff_execs = afl->fsrv.total_execs;
+
+  if (getenv("REPEAT_EFF")) repeat_eff = 1;
+  if (getenv("FUZZ_NEARBY")) fuzz_nearby = 1;
+
+  if (fuzz_nearby) {
+
+    non_eff_bytes = (u8 *)ck_alloc(sizeof(u8) * len);
+
+    // clean exec cksum
+    if (common_fuzz_stuff(afl, out_buf, len)) { return 0; }
+    prev_cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
+
+  }
+
+  do {
+
+    eff_round_continue = 0;
+    afl->stage_max = 32 * 1024;
+
+    for (; afl->stage_cur < afl->stage_max && afl->stage_cur < len;
+         ++afl->stage_cur) {
+
+      afl->stage_cur_byte = afl->stage_cur;
+
+      if (!inf_eff_map[afl->stage_cur_byte] ||
+          skip_eff_map[afl->stage_cur_byte])
+        continue;
+
+      if (is_det_timeout(before_det_time, 1)) { goto cleanup_skipdet; }
+
+      u8 orig = out_buf[afl->stage_cur_byte], replace = rand_below(afl, 256);
+
+      while (replace == orig) {
+
+        replace = rand_below(afl, 256);
+
+      }
+
+      out_buf[afl->stage_cur_byte] = replace;
+
+      before_skip_inf = afl->queued_items;
+
+      if (common_fuzz_stuff(afl, out_buf, len)) { return 0; }
+
+      out_buf[afl->stage_cur_byte] = orig;
+
+      if (fuzz_nearby) {
+
+        if (prev_cksum ==
+            hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST)) {
+
+          non_eff_bytes[afl->stage_cur_byte] = 1;
+
+        }
+
+      }
+
+      if (afl->queued_items != before_skip_inf) {
+
+        skip_eff_map[afl->stage_cur_byte] = 1;
+        afl->queue_cur->skipdet_e->quick_eff_bytes += 1;
+
+        if (afl->stage_max < MAXIMUM_QUICK_EFF_EXECS) { afl->stage_max *= 2; }
+
+        if (afl->stage_max == MAXIMUM_QUICK_EFF_EXECS && repeat_eff)
+          eff_round_continue = 1;
+
+      }
+
+      done_inf_map[afl->stage_cur_byte] = 1;
+
+    }
+
+    afl->stage_cur = 0;
+    done_eff = 1;
+
+    if (++eff_round_done >= 8) break;
+
+  } while (eff_round_continue);
+
+  new_hit_cnt = afl->queued_items + afl->saved_crashes;
+
+  afl->stage_finds[STAGE_QUICK] += new_hit_cnt - orig_hit_cnt;
+  afl->stage_cycles[STAGE_QUICK] += (afl->fsrv.total_execs - before_eff_execs);
+
+cleanup_skipdet:
+
+  if (fuzz_nearby) {
+
+    u8 *nearby_bytes = (u8 *)ck_alloc(sizeof(u8) * len);
+
+    u32 i = 3;
+    while (i < len) {
+
+      // assume DWORD size, from i - 3 -> i + 3
+      if (skip_eff_map[i]) {
+
+        u32 fill_length = (i + 3 < len) ? 7 : len - i + 2;
+        memset(nearby_bytes + i - 3, 1, fill_length);
+        i += 3;
+
+      } else
+
+        i += 1;
+
+    }
+
+    for (i = 0; i < len; i++) {
+
+      if (nearby_bytes[i] && !non_eff_bytes[i]) skip_eff_map[i] = 1;
+
+    }
+
+    ck_free(nearby_bytes);
+    ck_free(non_eff_bytes);
+
+  }
+
+  if (done_eff) {
+
+    afl->queue_cur->skipdet_e->continue_inf = 0;
+    afl->queue_cur->skipdet_e->done_eff = 1;
+
+  } else {
+
+    afl->queue_cur->skipdet_e->continue_inf = 1;
+
+  }
+
+  return 1;
+
+}
+